The following references to and descriptions of prior proposals or products are not intended to be, and are not to be construed as, statements or admissions of common general knowledge in the art. In particular, the following prior art discussion does not relate to what is commonly or well known by the person skilled in the art, but assists in the understanding of the inventive step of this disclosure of which the identification of pertinent prior art proposals is but one part.
Wheel frames for multiple directional wheels or omni-wheels generally include a hub having a main axis about which the multiple directional wheel is adapted to rotate; a hub rim radially surrounding the hub; a first plurality of peripheral roller supporting arms radially extending from the hub rim in a first plane, and a second plurality of peripheral roller supporting arms, each member arm of the second plurality of peripheral roller supporting arms having a radially inner base and being circumferentially offset with respect to diagonally adjacent members of the first plurality of peripheral roller supporting arms. The diagonally adjacent rollers overlap so that an operable portion of at least one of the rollers is in use in ground contact to enable the wheel to move in both a forward direction normal to the main axis by the rotation of the wheel as a whole about the main axis, and in a lateral direction having a vector component parallel to the main axis by the rotation of the at least one round contacting roller. The cost of manufacture of prior art multiple directional wheel frames is high, both in terms of time and materials. Inadequate ride quality is another factor in which prior attempts do not excel. Ride quality is directly related to roller pass-off length. Also, prior art attempts suffer from poor roller axle housing fit and impact resistance. These result in substantial wear and deterioration of the wheel and its performance: loosening axle mounts and impact damage discourage use of multiple applications where there is a low tolerance to mechanical failure or deterioration in performance. Furthermore, prior attempts tend to use metal components, such as axles, in engagement with moving components made of softer or weaker materials, thereby increasing cost and the likelihood of mechanical failure or accelerated wear and tear. It would be advantageous to provide a wheel frame that ameliorates one or more of the aforementioned disadvantages of the prior art or to at least provide a useful alternative thereto.